---
id: dependency-version-upgrades
title: Dependency Version Upgrades
---

## Babel

Our published packages only depend on `@babel/*` packages as devDependencies.
You can generally upgrade those dependencies with:

1. `yarn add -D @babel/code-frame @babel/core @babel/eslint-parser @babel/parser @babel/types`
2. `npx nx run ast-spec:test -u`

The fixtures under `packages/ast-spec/` describe how the files are parsed under both Babel and our (TSESTree) parser.

## ESLint

The typescript-eslint repository contains four kinds of version ranges for the `eslint` package:

- Integration tests: Pinned to our lowest supported ESLint version
- Packages with a `*` `peerDependency` version: These fall back to the explicit `peerDependency` versions
- Packages with explicit `peerDependency` versions: The full range of supported ESLint major versions
- [Root `package.json`](https://github.com/typescript-eslint/typescript-eslint/blob/main/package.json)'s' `devDependency`: A relatively recent release, used only for repository development

:::tip
Whenever you discover any new areas of work that are blocked by dropping an old ESLint version, such as new ESLint API deprecations, add a _TODO_ comment that will be caught by the regular expressions under [Removing Support for an Old ESLint Version](#removing-support-for-an-old-eslint-version).
:::

### Adding Support for a New ESLint Version

1. Upgrade the root `package.json` `devDependency` to the latest ESLint
1. Add the new major version to the explicit `peerDependency` versions
1. Check [`eslint-visitor-keys`](https://www.npmjs.com/package/eslint-visitor-keys) for a new version to be upgraded to as well.
1. Update [Users > Dependency Versions > ESLint](../users/Dependency_Versions.mdx#eslint)

### Removing Support for an Old ESLint Version

1. Increase the integration tests to the next lowest supported major version (`*.0.0`)
1. Remove the old major versions from packages with explicit `peerDependency` versions
1. Search for source code comments (excluding `CHANGELOG.md` files) that mention a now-unsupported version of ESLint.
   - For example, to remove support for v5, searches might include:
     - `/eslint.*5/i`
     - `/todo.*eslint.*5/i`
     - `/todo.*eslint/i`
1. Update [Users > Dependency Versions > ESLint](../users/Dependency_Versions.mdx#eslint)

See [chore: drop support for ESLint v6](https://github.com/typescript-eslint/typescript-eslint/pull/5972) for reference.

## Node

The typescript-eslint repository contains three kinds of version ranges for Node:

- [`.github/workflows/ci.yml`](https://github.com/typescript-eslint/typescript-eslint/blob/main/.github/workflows/ci.yml)'s `PRIMARY_NODE_VERSION`: Set to the highest Node version we support
- `node-version`: Set to a tuple of our [lowest, highest] supported versions for our unit tests in CI
- `engines` field in all `package.json`s: explicitly lists all supported Node ranges

Change those numbers accordingly when adding support for a new Node version or removing support for an old Node version.

See [feat: drop support for node v12](https://github.com/typescript-eslint/typescript-eslint/pull/5918) + [chore: test node v14 on ci.yml](https://github.com/typescript-eslint/typescript-eslint/pull/5512) for reference.

## TypeScript

### Adding Support for a New TypeScript Version

We generally start the process of supporting a new TypeScript version just after the first beta release for that version is made available.

1. Create and pin an issue with a title like _TypeScript X.Y Support_, `accepting prs`, `AST`, `dependencies`, and `New TypeScript Version` labels, and the following contents:

   1. A link to the _TypeScript X.Y Iteration Plan_ issue from the Microsoft issue tracker
   2. The following text:

      ```md
      This issue is just to track all of the new features and their implementation state in this project.
      As with all releases, we will not necessarily support all features until closer to the full release when everything the features are stabilised.

      _Please be patient._ ❤️
      ```

   3. A heading starting with `🔲 ` for each new TypeScript feature called out in the iteration plan that will impact us
   4. A heading titled _🔲 `lib.d.ts` Updates_ and the content _We will need to regenerate our types within `scope-manager`_
   5. A heading titled _Other changes with no impact to us_ containing a list of other changes that we don't believe will impact us

1. At this stage, it's fine to send and/or review PRs that implement necessary features, but wait to merge them until the new TypeScript version's RC is released
   - Whenever a PR is created, add ` (#1234)` to its respective heading, and change the heading's emoji from 🔲 to 🏗
   - Search for `expectBabelToNotSupport` to see how to support syntaxes not yet supported by Babel
1. Once the TypeScript RC version is released, start merging PRs
   - Whenever a PR is merged, change the respective heading's emoji from 🏗 to ✅
1. Create a PR with a title like `feat: update TypeScript to X.Y-rc` and the following changes:
   - In the root `package.json`, add `|| X.Y.2-rc2` to the `dependency` on `typescript`
   - In the root `package.json`, change the `devDependency` on `typescript` to `~X.Y.2-rc2`
   - Change the `SUPPORTED_TYPESCRIPT_VERSIONS` constant's `<` version to the next version of TypeScript
   - Change the `SUPPORTED_PRERELEASE_RANGES` constant to equal `['X.Y.2-rc']`
   - Rename and update `patches/typescript*` to the new TypeScript version
   - Run `yarn generate-lib` to update `scope-manager`
1. Once all PRs needed for the RC update PR are merged, merge the RC update PR
1. Once TypeScript releases the stable X.Y version, create and merge a PR with a title like `chore: bump TypeScript from X.YRC to X.Y` and the following changes:
   - In the root `package.json`, remove `|| X.Y.2-rc2` from the `dependency` on `typescript`, and bump its `<` version to the next version of TypeScript
   - In the root `package.json`, change the `devDependency` on `typescript` to `~X.Y.3`
   - Rename and update `patches/typescript*` to the new TypeScript version
   - Any other changes made necessary due to changes in TypeScript between the RC version and stable version
   - Update the supported version range in [Users > Dependency Versions](../users/Dependency_Versions.mdx)
1. Update [Users > Dependency Versions > TypeScript](../users/Dependency_Versions.mdx#typescript)
1. Send a PR that updates this documentation page to point to your newer issues and PRs
   - Also update any of these steps if you go with a different process

See for reference (caveat: these don't follow the exact process described here):

- [TypeScript 4.7 Support](https://github.com/typescript-eslint/typescript-eslint/issues/4800)
- [TypeScript 4.8 Support](https://github.com/typescript-eslint/typescript-eslint/issues/5227)
- [feat: support TypeScript 4.8](https://github.com/typescript-eslint/typescript-eslint/pull/5551)
- [feat: support TypeScript 4.9](https://github.com/typescript-eslint/typescript-eslint/pull/5716)
- [chore: bump TS from 4.9RC to 4.9](https://github.com/typescript-eslint/typescript-eslint/commit/a40a311bb52a2b1cfac43851b201f8cfc96c8d5d)

### Removing Support for an Old TypeScript Version

A single PR can remove support for old TypeScript versions as a breaking change:

1. Update the root `package.json` `devDependency`
1. Update the `SUPPORTED_TYPESCRIPT_VERSIONS` constant in `warnAboutTSVersion.ts`
1. Update the `versions` constant in `version-check.ts`
1. Update [Users > Dependency Versions > TypeScript](../users/Dependency_Versions.mdx#typescript)
1. Search for source code comments (excluding `CHANGELOG.md` files) that mention a now-unsupported version of TypeScript.
   - For example, to remove support for v4.3, searches might include:
     - `4.3`
     - `/is.*4.*3/i`
     - `/semver.*4.*3/i`
     - `/semver.satisfies/`
     - `/todo.*ts/i`
     - `/todo.*typescript/i`

See [feat: bump minimum supported TS version to 4.2.4](https://github.com/typescript-eslint/typescript-eslint/pull/5915).
